This invention relates to a mobile cleaning and treating unit and more particularly to a unit for high pressure spray application in the cleaning and treating of large structures, such as mobile homes, trucks, automobiles, buildings, and the like. Through a novel control system and valving arrangement different cleaning and treating agents can be introduced to the spray.
Mobile units suitable for on-site cleaning and treating operations are shown in U.S. Pat. Nos. 3,481,544 and 3,567,342, granted to Otto V. Jackson and assigned to the assignee of this application. These units are compact and self-contained, each carrying its own water, cleaning and treating compounds, and the like, as well as power to produce a high pressure spray even with long hose lengths that are often necessary when large structures are being cleaned. Cleaning with units of this type is more efficient than using existing on-site water pressure; in particular, relatively high pressures are attainable with positive displacement pumps carried by the mobile unit, the water can be heated, and correct proportions of various cleaning or treating agents can be conveniently added during application. A relatively compact mobile van houses and carries washing equipment, which is fixed within the van, except for one or more spray hoses with remote applicators and control valves. The pumps that provide the high pressure spray are driven from motors operated from electricity generated from a power unit in the truck. Unloader valves are provided with the positive displacement pumps to permit operation of the pumps while the spray outlet is turned off. This affords flexibility of operation without overloading the pumps and driving motors. In such vans, provision has been made for mixing liquid cleaner with water as the water is drawn from a storage tank carried by the truck and supplied to the hose and applicator by the pumps. In the units disclosed in the aforementioned patents, this was accomplished by opening a solenoid-operated valve to allow introduction of detergent or the like to the pump. Pump controls would determine the amount of detergent introduced. The solenoid valve was opened by a switch on a cord to a control box for the valve so that detergent could be added by the operator at the spray nozzle remote from the truck. While such an arrangement functioned satisfactorily, it had the disadvantages of introducing only one chemical unless the operator returned to the mobile unit to change the contents of the container of liquid cleaner, and it required a separate control and cord to be carried by the operator to selectively introduce the detergent, which was difficult to keep untangled and created an electrical hazard. In a subsequent construction plural sources of chemicals were provided with valves operated by remote radio control. However, the chemicals from the different sources were supplied in the same ratio or the operator was required to return to the mobile unit to adjust the inlet control to the pump from the supplies to change the ratio, negating the advantage of remote selection. Further, the radio control was not suited for use in the environment and suffered breakage or water damage. Often the batteries of the portable transmitter would go dead, the transmitter frequency was often misaligned, the operator would sometimes leave without the transmitter, and stray radio signals would operate the valves.
The present invention provides a control system for introducing individually adjustable proportional amounts of liquid additives from a number of separate containers to a pressurized flow of liquid being applied to a structure, such as a building, vehicle, or the like, without separate controls for selection, but rather utilizing the flow control valve for the applicator spray. In a preferred embodiment, the pressurized flow is provided from a tank of water, by a motor driven pump associated with a main conduit for supplying water to an outlet. A flexible hose with a trigger-operated flow-control valve and applicator nozzle is attached to the outlet and used for applying the fluid to the structure being cleaned or treated.
A plurality of containers, four in the preferred embodiment, contain cleaning and treating chemicals. Each container communicates with a common conduit through an electrically operable control valve that has a mechanical adjustment for throttling passage of fluid that flows from the container through the valve to the main conduit. A switch-operated sequence control electrically operates the control valves, each separately in succession, in response to the initiation of flow in the main conduit. The sequence control also includes a condition in the sequence in which no electrically operable control valve is opened. Thus, each time the flow of liquid is initiated from the flow control valve of the applicator, a different one or none of the control valves of the separate containers is opened to introduce fluid from a particular container or to prevent introduction from any container to the main flow. Preferably, the containers are filled with appropriate chemicals so the sequence of operation of the valves corresponds with the normal sequence of use of the chemicals in a cleaning or treating operation. This is not necessary, however, because by momentarily triggering a flow of fluid, a successive valve may be opened and the operator can thereby conveniently progress to any desired chemical or to a condition where none of the valves is opened and only the flow of fluid from the main tank is provided.
Advantageously, the control valves from each of the containers is a solenoid controlled diaphragm valve that incorporates a needle valve control for adjusting the flow of chemical through the valve. Each valve is connected to a common conduit that then connects to the main conduit through a venturi so that flow through the main conduit draws fluid in desired proportion from the appropriate container through one of the opened solenoid-operated valves and the common conduit.
With the present invention it is possible for the operator to remotely and conveniently control the selection of additives in proper proportions to his primary liquid supply without leaving his position at the applicator and without the need for a separate electrical cable and switch or radio controlled system.